rpi-base: wic: generate entries for device tree files
rpi-base: wic: generate entries for device tree files

Augment IMAGE_BOOT_FILES with entries picking up proper dtb[o]s. This allows for
building usable wic images once again.

Signed-off-by: Maciej Borzecki <f609d9f713abcd5f8f0e51f08dc151638a7681e7@rndity.com>

leon-anavi/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,leon-anavi/meta-raspberrypi,d21d3q/meta-raspberrypi,d21d3q/meta-raspberrypi,schnitzeltony/meta-raspberrypi,d21d3q/meta-raspberrypi,agherzan/meta-raspberrypi,kraj/meta-raspberrypi,agherzan/meta-raspberrypi,kraj/meta-raspberrypi,schnitzeltony/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,agherzan/meta-raspberrypi,agherzan/meta-raspberrypi,leon-anavi/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,agherzan/meta-raspberrypi,LocutusOfBorg/meta-raspberrypi,schnitzeltony/meta-raspberrypi,agherzan/meta-raspberrypi,d21d3q/meta-raspberrypi,kraj/meta-raspberrypi